Organic el device and method for manufacturing the same

ABSTRACT

A sealing layer covers more surely both of a display region and a peripheral region on a substrate. A dummy structure is formed in the peripheral region of the substrate. The dummy structure contains, for instance, at least one of the materials constituting an organic EL display structure. The dummy structure is located in the peripheral region so that the volume per unit area of the sealing layer in the peripheral region is substantially the same as that in the display region.

This application is a Continuation of copending application Ser. No.12/514,567 filed on May 12, 2009, which is the U.S. National Phase ofPCT/JP2007/073073, filed Nov. 29, 2007, and which claims priority toApplication No. 2006-323492 filed in Japan, on Nov. 30, 2006. The entirecontents of all of the above applications are hereby incorporated byreference.

TECHNICAL FIELD

The present invention relates to an EL (Electroluminescent) device suchas an organic EL display or the like.

BACKGROUND ART

An organic EL device includes a plurality of pixel circuits, at leastone first electrode, a plurality of organic EL elements, and at leastone second electrode, which are formed on the same side of a firstsubstrate.

An organic EL device uses a configuration in which a sealing glasssubstrate is bonded to said first substrate formed said organic ELelements in order to protect said organic EL elements from moisture andoxygen.

An organic EL device has a display region and a peripheral region aroundsaid display region. When said sealing glass substrate is bonded to saidfirst substrate, a bonding configuration is utilized, in which an epoxyresin is applied to said peripheral region of a display region, or atransparent resin is applied over both of said display region and saidperipheral region.

Examples of related art of the present invention include the techniquesdescribed in Patent Document 1 (Japanese Unexamined Patent PublicationNo. 2004-111119) and Patent Document 2 (Japanese Patent No. 3705190).

DISCLOSURE OF INVENTION

In a bonding configuration in which a transparent resin is applied overboth of said display region and said peripheral region, it is requiredto fill substantially the whole area of the substrate with the resin inorder to enhance product reliability. This is because if there is a voidin the resin on said display region and said peripheral region, moistureand oxygen can easily enters the EL device through the void.

In order to solve the problem, an organic EL device according to a firstembodiment of the present invention comprises a first substratecomprising a display region and a peripheral region, an organic ELdisplay structure located in the display region of the first substrate,a second substrate, and a sealing layer in the space between said twosubstrates disposed to seal the organic EL display structures thatcovers both of said display region and said peripheral region and fixessaid second substrate to said first substrate, wherein a dummy structureis located in the peripheral region so that the sealing layer in theperipheral region has substantially the same volume per unit area asthat in the display region.

A method for manufacturing an organic EL device according to a secondembodiment of the present invention comprises an act of forming anorganic EL display structure in a display region of a first substratecomprising the display region and a peripheral region, an act of forminga dummy structure in the peripheral region of the first substrate sothat the dummy structure in the peripheral region has substantially thesame volume per unit area as the organic EL display structure in thedisplay region, an act of applying a sealing material to a secondsubstrate, and an act of bonding the second substrate to the firstsubstrate with the sealing material so as to seal the organic EL displaystructure and the dummy structure and to fill the space between thefirst substrate and the second substrate with the sealing material.

An organic EL device according to a third embodiment of the presentinvention comprises a first substrate comprising a display region and aperipheral region, an organic EL display structure located in thedisplay region of the first substrate, a sealing layer disposed to sealthe organic EL display structure and cover the display region and theperipheral region of the first substrate, and a second substrate fixedto the first substrate with the sealing layer, wherein a dummy structurecomprising at least one of the element structures of the organic ELdisplay structure is located in the peripheral region, the space betweenthe first and second substrates being filled with the sealing layer.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic plan view showing the whole configuration of anorganic EL device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG. 1.

FIG. 3 is an enlarge schematic plan view of a principal portion shown inFIG. 1.

FIG. 4 is a drawing showing an act for manufacturing the organic ELdevice shown in FIG. 1.

FIG. 5 is a drawing showing an act for manufacturing the organic ELdevice shown in FIG. 1.

FIG. 6 is a drawing showing an act for manufacturing the organic ELdevice shown in FIG. 1.

FIG. 7 is a drawing showing an act for manufacturing the organic ELdevice shown in FIG. 1.

FIG. 8 is a drawing showing an act for manufacturing the organic ELdevice shown in FIG. 1.

FIG. 9 is a drawing showing an act for manufacturing the organic ELdevice shown in FIG. 1.

FIG. 10 is a drawing showing an act for manufacturing the organic ELdevice shown in FIG. 1.

FIG. 11 is a drawing showing an application example of the organic ELdevice shown in FIG. 1.

BEST MODE FOR CARRYING OUT THE INVENTION

An organic EL device and a method for manufacturing the same accordingto an embodiment of the present invention are descried below.

<Configuration of Organic EL Device>

An organic EL device 10 includes a first substrate 12, an organic ELdisplay structure 18, a dummy structure 36, a sealing layer 40, and asecond substrate 50. The organic EL device 10 uses a top emission-typestructure in which light emitted from an organic EL element 24 includedin the organic EL display structure 18 is emitted to outside through thesealing layer 40 and the second substrate 50 which are disposed in anupper portion. Although, in this embodiment, the organic EL device 10 isdescribed on the assumption that it uses an active matrix drivingsystem, a passive matrix driving system may be used.

The first substrate 12 is a glass substrate or the like and has asubstantially rectangular plate shape. The first substrate 12 includes adisplay region 13, a peripheral region 15, and an external pads region16. More specifically, the substantially rectangular display region 13is disposed substantially at the center of the first substrate 12, andthe peripheral region 15 is disposed to surround the display region 13.In addition, the external pads region 16 is disposed in the two sideportions which hold a predetermined corner of the first substrate 12therebetween (in FIG. 1, the right side portion and the bottom sideportion which hold the lower right corner therebetween). The organic ELdisplay structure 18 is formed in the display region 13 and the dummystructure 36 is formed in the peripheral region 15. The display region13 is a region where the organic EL display structure 18 including theorganic EL element 24 which emits light is formed. The peripheral region15 is a region where the dummy structure 36 which does not emit light isformed.

The organic EL display structure 18 is formed in the display region 13of the first substrate 12 and is a structural portion for emissiondisplay in the organic EL device 10. The organic EL display structure 18includes as element structures a circuit layer 20, a first insulatinglayer 22 (planarization layer), the organic EL element 24, a secondinsulating layer 28 (interlayer insulating layer), and a spacer portion30. The display region 13 of the first substrate 12 is partitioned intoa plurality of pixels forming regions arranged in a matrix including aplurality of rows and a plurality of columns. The organic EL element 24is formed in each of the pixel forming regions. The spacer portion 30 isformed in a lattice shape so as to partition the respective pixelforming regions.

The circuit layer 20 is formed on the first substrate 12 and constitutesa thin film transistor and a part of a capacitor element correspondingto each pixel. Further, a wiring portion (not shown) connected to eachcircuit layer 20 is formed on the first substrate 12. In addition, aprotective layer (not shown) is formed on the first substrate 12 onwhich the circuit layers 20 are formed.

The first insulating layer 22 is provided on the first substrate 12 soas to cover the circuit layers 20. The first insulating layer 22 has thefunction to planarize the first substrate 12 on the upper surface ofwhich the circuit layers 20 are formed and to insulate the organic ELelements 24 from the first substrate 12. The first insulating layer 22is made of an inorganic material such as silicon oxide, silicon nitride,or the like, or an insulating resin. The first insulating layer 22 mayhave either a single-layer structure or a multilayer structure. When thefirst insulating layer 22 has a multilayer structure, a portion of thelayers may be used as a constituent of the dummy structure 36.

In addition, in the first insulating layer 22, contact holes 22 h areformed for connecting first electrode layers 23, which will be describedbelow, to the circuit layers 20.

The organic EL elements 24 are formed on the first insulating layer 22and each include the first electrode layer 23, an organic layer 25, anda second electrode layer 26.

The first electrode layers 23 are formed on the first insulating layer22 and constitute lower electrodes of the organic EL elements 24. Thefirst electrode layers 23 are electrically connected to the circuitlayers 20 through the contact holes 22 h.

In addition, the second insulating layer 28 made of a resin or the likeis formed on the first insulating layer 22 and the first electrodelayers 23. The second insulating layer 28 has apertures 28 hcorresponding to the respective pixels, and the organic layer 25 and thesecond electrode layer 26 are formed in each of the apertures 28 h.

The organic layer 25 includes a light-emitting layer containing anorganic material as an illuminant. The organic layer 25 is disposed toadhere to the first electrode layer 23 so as to make surface contactwith the first electrode layer 23 in each of the apertures 28 h. Theouter periphery of the organic layer 25 overlaps the periphery of eachaperture 28 h in the second insulating layer 28, causing a state ofnon-contact with the first electrode layer 23. Therefore, a portion ofthe organic layer 25 which overlaps the second insulating layer 28 andis in non-contact with the first electrode layer 23 does not emit light.Namely, the second insulating layer 28 defines the emission regions ofthe organic EL elements 24.

The organic layer 25 may have either a single layer structure or amultilayer structure including laminated layers having differentfunctions. When the organic layer 25 has a multilayer structure, it maycontain a portion made of an inorganic material, and the organic layer25 may thus have such a structure with an inorganic material.

The second electrode layer 26 is formed on the organic layer 25 using aconductive material with light transmissivity, such as indium tin oxide(ITO), tin oxide, or the like, so that light is emitted from the uppersurface side of the organic layer 25. Even if the second electrode layer26 is made of a material which little transmits light, such asmagnesium, silver, aluminum, or the like, the formation of a thin layerhaving a thickness of 100 nm or less can impart light transmissivity tothe second electrode layer 26 while securing conductivity to someextent.

The spacer portion 30 is formed in a lattice shape using an insulatingresin. The spacer portion 30 has the function to separate between thesecond electrode layers 26 and the function to mount and support a metalmask when the organic layers 25 are formed by evaporation. Whenattention is paid to the function to separate between the secondelectrode layers 26, the spacer portion 30 may be referred to as aseparator. Therefore, in order to separate between the second electrodelayers 26, the spacer portion 30 may be formed in a trapezoidal shape inwhich the top of the spacer portion 30 is wider than the bottom thereof.Of course, the spacer portion 30 may have only the function to mount andsupport a metal mask. The spacer portion 30 is provided according todemand and may be omitted.

In addition, a protective layer (not shown) is formed on the surface ofthe organic EL display structure 18.

The peripheral region 15 of the first substrate 12 includes a peripheralfilled region 17. In this embodiment, substantially the whole of theperipheral region is the peripheral filled region 17. In other words,the peripheral filled region 17 is formed to substantially surround thedisplay region 13, which means not only the case in which the peripheralfilled region 17 surrounds the display region 13 with no space but alsothe case in which the peripheral filled region 17 surrounds the displayregion 13 with one or more spaces. This applies to the case in which alinear dummy structure 36 a and a peripheral seal portion substantiallysurround the display region 13. The dummy structure 36 is formed in theperipheral filled region 17.

As described in detail below, the dummy structure 36 has the function tocontrol the volume per unit area of the sealing layer 40 in theperipheral filled region 17 so that the volume per unit area issubstantially the same as the volume per unit area of the sealing layer40 in the display region 13. The dummy structure 36 is composed of atleast one of the element structures of the organic EL display structure18. In other words, a material constituting the dummy structure 36contains at least one of the materials of the organic EL displaystructure 18.

In this embodiment, the dummy structure 36 includes two types ofstructures, i.e. linear dummy structures 36 a provided on the innerperipheral side of the peripheral filled region 17 and dot-like dummystructures 36 b provided on the outer peripheral side of the peripheralfilled region 17.

The linear dummy structures 36 a each include, as the constituentstructures, the first insulating layer 22, the second insulating layer28, and the spacer portion 30. Namely, when the organic EL displaystructure 18 is formed, the first insulating layer 22, the secondinsulating layer 28, and the spacer portion 30 are formed also in theperipheral filled region 17, thereby forming the linear dummy structures36 a.

In addition, the first insulating layer 22, the second insulating layer28, and the spacer portion 30 which constitute the linear dummystructures 36 a are formed on the inner side of the peripheral filledregion 17 in a zigzag shape alternately bending inward and outward andthey substantially surround the display region 13.

The dot-like dummy structures 36 b each include, as the constituentstructures, the first insulating layer 22 and the spacer portion 30.Namely, when the organic EL display structure is formed, the firstinsulating layer 22 and the spacer portion 30 are laminated also in theperipheral filled region 17, thereby forming the dot-like dummystructures 36 b.

In addition, the first insulating layer 22 and the spacer portion 30which constitute the dot-like dummy structures 36 b are formed on theouter side of the peripheral filled region 17 so as to be scattered at aplurality of positions and to surround the display region 13. Morespecifically, the dot-like dummy structures 36 b are formed at apredetermined pitch along a plurality (here, two) of lines on the outerperipheral side of the peripheral filled region 17 so that the dot-likedummy structures 36 b along one of the lines are deviated from thosealong the other line by half pitch.

The sealing layer 40 is made of a transparent resin or the like andcharged in a space between the second substrate 50 or the organic ELdisplay structure 18 and the dummy structure 36 on the first substrate12. Therefore, the sealing layer 40 is disposed to seal the organic ELdisplay structure 18 and the dummy structure 36 and to cover the displayregion 13 and the peripheral filled region 17 of the first substrate 12.

The second substrate 50 is made of a transparent substrate such as aglass substrate or the like and is formed in a shape corresponding tothe display region 13 and the peripheral region 15. The second substrate50 is fixed to the first substrate 12 through the sealing layer 40. Amain surface of the second substrate 50 on which the sealing layer 40 isformed is formed in a substantially flat surface. Being substantiallyflat means not only the case where the surface is strictly completelyflat but also the case where the maximum difference of elevation ofirregularity formed on the second substrate 50 is 3 μm or less.Therefore, when the first substrate 12 and the second substrate 50 arebonded together, a sealing material flows along a main surface of thesecond substrate 50 and easily flows into recess portions, and thus thespace between the first substrate 12 and the second substrate 50 can besufficiently filled with the sealing material.

In addition, in the organic EL device 10, when the dummy structure 36 isformed, the areal ratio of the dummy structure 36 on the first substrate12, the configuration (height and the like) of the dummy structure 36,or the like is controlled so that the volume per unit area of thesealing layer 40 in the display region 13 is substantially the same asthe volume per unit area of the sealing layer 40 in the peripheralfilled region 17. Namely, consideration is made on the basis of theorganic EL display structure 18 and the dummy structure 36, the dummystructure 36 is formed on the first substrate 12 so that the volume perunit area of the organic EL display structure 18 in the display region13 is substantially the same as the volume per unit area of the dummystructure 36 in the peripheral filled region 17. The unit area as areference is, for example, 1 mm².

Here, the expression that the volume per unit area of the sealing layer40 in the display region 13 is substantially the same as the volume perunit area of the sealing layer 40 in the peripheral filled region 17means the following: the second substrate 50 on which the sealingmaterial is substantially uniformly applied is superposed on the firstsubstrate 12, and both in the display region 13 and in the peripheralfilled region 17, the space between the first substrate 12 and thesecond substrate 50 is able to be fully filled with the sealingmaterial.

Therefore, the expression that the volume per unit area of the sealinglayer 40 in the display region 13 is substantially the same as thevolume per unit area of the sealing layer 40 in the peripheral filledregion 17 means not only the case where both volumes per unit area arestrictly the same but also the case where both volumes per unit area arewithin a predetermined allowable range.

As a result of an experiment, the inventor of the present inventionfound that when the ratio ((volume per unit area of the sealing layer 40in the peripheral filled region 17)/(volume per unit area of the sealinglayer 40 in the display region 13)) is 0.81 to 1.09, the peripheralfilled region 17 is able to be fully filled with the sealing layer 40,while when the volume per unit area ratio is 1.18 to 1.20, there occursa space that cannot be fully filled with the sealing layer 40 in theperipheral filled region 17. Namely, when the volume per unit area ratiois in the range of 0.81 to 1.09, both the display region 13 and theperipheral filled region 17 can be sufficiently filled with the sealinglayer 40.

Therefore, the expression that the volume per unit area of the sealinglayer 40 in the display region 13 is substantially the same as thevolume per unit area of the sealing layer 40 in the peripheral filledregion 17 includes the case where the ratio of the volume per unit areaof the sealing layer 40 in the peripheral filled region 17 to the volumeper unit area of the sealing layer 40 in the display region 13 is 0.81to 1.09.

Therefore, the volume per unit area of the sealing layer 40 in theperipheral filled region 17 may be changed within the above range asdescribed below.

The peripheral region 15 includes a first peripheral region 15 a and asecond peripheral region 15 b more apart from the display region 13 thanthe first peripheral region 15 a. In the peripheral region 15, the innerside on which the linear dummy structures 36 a are formed corresponds tothe first peripheral region 15 a. The outer side on which the dot-likedummy structures 36 b are formed corresponds to the second peripheralregion 15 b.

The volume per unit area which can be filled with the sealing layer 40in the second peripheral region 15 b is larger than the volume per unitarea which can be filled with the sealing layer 40 in the firstperipheral region 15 a. Namely, when consideration is made on the basisof the dummy structure 36, on the first substrate 12, the volume perunit area of the dot-like dummy structures 36 b in the second peripheralregion 15 b is smaller than the volume per unit area of the linear dummystructures 36 a in the first peripheral region 15 a. In this embodiment,the linear dummy structures 36 a are formed in the first peripheralregion 15 a, and the dot-like dummy structures 36 b are formed in thesecond peripheral region 15 b. Thus, the volume per unit area to befilled in the second peripheral region 15 b is larger than the volumeper unit area to be filled in the first peripheral region 15 a.

Therefore, when the second substrate 50 to which the sealing material issubstantially uniformly applied is bonded to the first substrate 12, thefirst peripheral region 15 a having a smaller volume per unit area to befilled than that of the second peripheral region 15 b is more securelyfilled with the sealing material. In the second peripheral region 15 bhaving a larger volume per unit area to be filled than that of the firstperipheral region 15 a, the space between the first substrate 12 and thesecond substrate 50 is more securely filled with the sealing materialapplied to the second substrate 50, with causing little protrusion ofthe sealing material in the side direction.

Both the first peripheral region 15 a and the second peripheral region15 b don't have to be present in the peripheral filled region 17. Forexample, only the first peripheral region 15 a may be present in theperipheral filled region 17 and the condition in which the sealing layervolume per unit area in the first peripheral region 15 a issubstantially the same as in the display region 13 may be satisfied.Further, the second peripheral region 15 b may be outside of theperipheral filled region 17 and the condition in which the sealing layervolume per unit area in the second peripheral region 15 b issubstantially the same as in the display region 13 may not be satisfied.In this case, the second peripheral region 15 b may not be fully filledwith the sealing material. Of course, such a structure may be used. Inconsideration of such a case, the volume per unit area to be filledmeans the volume per unit area between the dummy structure 36 on thefirst substrate 12 and the second substrate 50, which can be filled withthe sealing material.

From another viewpoint, the dummy structures 36 a and 36 b are formed sothat the volume per unit area of the sealing layer 40 in the peripheralregion 15 is substantially the same as the volume per unit area of thesealing layer 40 in the display region 13, and the space between thefirst substrate 12 and the second substrate 50 is filled with thesealing layer 40. In this case, the above-mentioned condition doesn'thave to be satisfied by forming the dummy structures 36 a and 36 b overthe whole of the peripheral region 15, and the above-mentioned conditionmay be satisfied by forming the dummy structures 36 a and 36 b in aportion of the peripheral region 15. This applies to the volume per unitarea ratio and the like which will be described below.

The second peripheral region 15 b is preferably set in a region of 0.5mm or less from the edge of the organic EL device 10. When a glass plateis divided to produce a plurality of organic EL devices 10, it iseffective to set the second peripheral region 15 b inside of a divisionline. When the second peripheral region 15 b is formed inside of adivision line, it is possible to effectively reduce the occurrence ofdivision defects due to protrusion of the sealing material from thedivision line, thereby reducing deterioration of the manufacture yield.

In the organic EL device 10, peripheral sealing portions 54 are formedaround the display region 13, the sealing layer 40 being in directcontact with the first substrate 12 in the peripheral sealing portions54. In this embodiment, the peripheral sealing portions 54 are formed ina substantially rectangular frame shape between the display region 13and the innermost linear dummy structure 36 a, between the linear dummystructures 36 a, between the outermost linear dummy structure 36 a andthe dot-like dummy structures 36 b along the innermost line, and betweenthe respective lines along which the dot-like dummy structures 36 b areformed. The peripheral sealing portions 54 preferably substantiallysurround the display region.

In each of the peripheral sealing portions 54, the element structuresconstituting the organic EL display structure 18 are not formed, and thesealing layer 40 is in direct contact with the first substrate 12. Inaddition, a protective layer or the like composed of an inorganicmaterial, such as silicon nitride, silicon oxynitride, silicon oxide, orthe like, may be formed on the first substrate 12. Namely, theexpression “the sealing layer 40 is in direct contact with the firstsubstrate 12” represents the case where both are in contact without thebasic element structures constituting the organic EL display structure18 therebetween and includes the case where a protective layer or thelike which does not substantially adversely affect entering anddiffusion of moisture or oxygen is interposed between the sealing layer40 and the first substrate 12.

Further, each of the circuit layers 20, the first electrode layers 23,and the second electrode layers 26 is connected to line (not shown). Theline is appropriately extended to the external pads region 16 andconnected to an outside driver circuit or the like in the external padsregion 16. The driver circuit or the like may be formed in the externalpads region 16.

<Method for Manufacturing Organic EL Device>

The method for manufacturing the organic EL device 10 is describedbelow. Although detailed steps are described, the organic EL device 10and the manufacturing method therefor are not limited to these steps.

First, the organic EL display structure 18 is formed on the displayregion 13 of the first substrate 12. At the same time, the dummystructure 36 is formed on the peripheral region 15 of the firstsubstrate 12.

More specifically, as shown in FIG. 4, the circuit layer 20 is formed asa backplane circuit for deriving each of the organic EL elements 24 onthe first substrate 12, such as a glass substrate or the like. Thecircuit layers 20 are formed by forming an element group includingbottom-gate back channel etch-type TFTs using amorphous silicon. Abottom-gate back channel etch-type TFT circuit has a six-layer structureincluding a gate electrode, a silicon nitride layer, hydrogenatedamorphous silicon, N-type amorphous silicon for contact, a drain/sourceelectrode, and a silicon nitride passivation layer. Then, a protectivelayer such as an inorganic passivation layer or the like is formed onthe first substrate 12 on which the circuit layers 20 are formed.

Then, as shown in FIG. 5, in order to planarize the first substrate 12,a photosensitive resin is applied over the entire region of the firstsubstrate 12. Then, the photosensitive resin is removed from onlyportions corresponding to the contact holes 22 h by exposure anddevelopment. As a result, the first insulating layer 22 constituting theorganic EL display structure 18 and the dummy structure 36 in thedisplay region 13 and the peripheral region 15, respectively, is formed.As the photosensitive resin, positive acrylic resin is applied to athickness of 4 exposed to UV light, and then developed with TMAH(tetramethylammonium hydroxide). In the exposure and development step,the first insulating layer 22 is removed from the contact holes 22 h, aportion not containing the first insulating layer 22 in the peripheralregion 15, the external pads region 16, and the like. The acrylic resinis fired in a convection oven at 230° C. for 30 minutes. Consequently,underlying TFTs can be planarized, and disconnection and electrodeshort-circuiting due to the steps formed by the circuits of the organicEL display structure 18 can be reduced. As the first insulating layer22, instead of the acrylic resin, a siloxane polymer, a silicon nitridelayer, or the like may be used.

The first insulating layer 22 covers the whole of the display region 13excluding the contact holes 22 h in order to planarize the circuits inthe display region 13. On the other hand, in the peripheral region 15,as described above, the first insulating layer 22 is appropriatelyremoved in a predetermined pattern in order to control the volume perunit area of the sealing layer 40 in the peripheral region 15.

Next, as shown in FIG. 6, the first electrode layers 23 are formed. Inthis step, AlNd is deposited by sputtering over the entire surface ofthe substrate under the manufacturing process and patterned by aphotolithography process. As a photoresist, a positive novolac resin isused, exposed to UV light, and developed with THAM. AlNd is patterned bywet etching with a mixed solution of phosphoric acid, nitric acid, andacetic acid, and then removing the resist. As a first electrode, Al, anAl alloy (containing Nd, Ni, Y, Gd, or Pd), Ag, an Ag alloy (containingPd or Cu), Mo, or the like can be used.

Next, as shown in FIG. 7, the second insulating layer 28 is formed. Thesame photosensitive resin as that used for forming the first insulatinglayer 22 is applied to a thickness of 1.5 μm on the substrate under themanufacture, exposed to UV light, and then developed with TMAH. Theresin is fired in a convection oven at 230° C. for 30 minutes. As thesecond insulating layer 28, like the first insulating layer 22, asiloxane polymer, a silicon nitride layer, or the like may be usedinstead of the photosensitive resin.

The second insulating layer 28 is provided for insulating a portionother than the light-emitting portion of the organic layer 25, where thefirst electrode layer 23 and the second electrode layer 26 overlap eachother. In the display region 13, the second insulating layer 28 isremoved from the light-emitting portion of the organic layer 25. In aconfiguration of the organic EL display structure, if required, thesecond insulating layer 28 is removed from a contact hole for connectingthe second electrode layer 26 to lower line.

On the other hand, in the peripheral region 15, as described above, thesecond insulating layer 28 is appropriately removed in a predeterminedpattern in order to control the volume per unit area of the sealinglayer 40 in the peripheral region 15.

Then, as shown in FIG. 8, the spacer portions 30 are provided. Thespacer portions 30 are adapted for reducing damage to the organic layers25 due to contact with a metal mask when the organic layers 25 areformed by evaporation using the metal mask. During evaporation, themetal mask is mounted and supported on the spacer portions 30 apart fromthe organic layers 25.

As a material of the spacer portions 30, a negative acrylic resin havinga dissolution rate in a developer which is decreased by lightirradiation, a siloxane polymer, or a negative novolac resin, or thelike can be used.

A negative novolac resin is used as the material of the spacer portions30, and then patterned to form the spacer portions 30 having atrapezoidal shape in which the top is wider than the bottom. The spacerportions 30 are formed in a lattice pattern to surround the organic ELelements 24, and thus pixel separation can be realized by thetrapezoidal spacer portions 30 without patterning of the secondelectrode layer 26.

If the spacer portions 30 are provided with only the function to supportthe metal mask, of course, the area required for forming the spacerportions 30 can be decreased.

As described above, in the display region 13, the spacer portions 30 areformed in a lattice shape on the second insulating layer 28. On theother hand, in the peripheral region 15, as described above, the spacerportions 30 are appropriately removed in a predetermined pattern inorder to control the volume per unit area of the sealing layer 40 in theperipheral region 15.

Then, the substrate under manufacture is annealed under a temperaturecondition of 230° C. The annealing may be performed in a nitrogenatmosphere or an air atmosphere.

Next, the annealed substrate is washed before evaporation. The washingis performed with, for example, water or functional water such as ozonewater or the like. In addition to the washing with functional water,treatment with UV, ozone, or the like may be performed for removingorganic substances on the first electrode layers 23.

Next, the washed substrate is baked in vacuum to remove moistureremaining after the washing, and as shown in FIG. 9, the organic layers25 and the second electrode layers 26 are formed. In this step, theorganic layers 25 and the second electrode layers 26 are formed in thedisplay region 13 and not formed in the peripheral region 15. Theorganic layers 25 and the second electrode layers 26 can be formed anyone of various techniques including known techniques.

Through the above steps, the organic EL display structure 18 and thedummy structure 36 are formed on the first substrate 12. In other words,the dummy structure 36 is formed in the same steps as those for formingthe organic EL display structure 18 on the first substrate 12.

After the second electrode layers 26 are formed, a silicon nitride layeris formed to a thickness of 3 μm by CVD to form a protective layer ofthe organic EL elements 24. More specifically, the protective layer canbe deposited by capacitive coupled plasma CVD using silane and ammoniaor nitrogen.

On the other hand, as shown in FIG. 10, a sealing material is applied ina substantially uniform thickness to a main surface of the secondsubstrate 50.

The second substrate 50 may be made of plain glass without a pattern orglass provided with a black matrix made of a Cr laminated layer orprovided with a color filter. In this embodiment, plain glass on whichonly a process mark is formed without a pattern being formed in adisplay portion is used. As the sealing material 52, a UV-curable epoxyresin, a thermosetting resin, or the like can be used. Herein, aUV-curable epoxy resin is used.

The sealing material 52 is applied to a main surface of the secondsubstrate 50 by screen printing. The thickness of the sealing material52 is determined so that the sealing material is flat after printing,and irregularity formed by the organic EL display structure 18 on thefirst substrate 12 can be sufficiently offset. For example, when adifference of elevation in irregularity in the emission portion on thefirst substrate 12 is 5 μm, printing may be performed so that thethickness of the sealing material 52 after coating is 7 μm. When thesecond substrate 50 has irregularity, for example, when a color filteris formed on the second substrate 50, the sealing material 52 may beapplied thickly. When the first substrate 12 has small irregularity, forexample, when the spacer portions 30 are not formed on the firstsubstrate 12, a thickness of about 3 μm is sufficient for the sealingmaterial 52 after coating. Namely, the thickness of the sealing material52 is appropriately controlled to a thickness which permits filling inirregularity according to irregularity on the first substrate 12 andirregularity on the second substrate 50.

Then, the second substrate 50 is fixed to the first substrate 12 throughthe sealing material 52 so as to seal the organic EL display structure18 and the dummy structure 36.

More specifically, the first substrate 12 on which the organic ELdisplay structure 18 and the dummy structure 36 are formed and thesecond substrate 50 on which the sealing material 52 is applied arebonded together in a nitrogen atmosphere. When the sealing material 52is a resin which is cured immediately after UV irradiation, the sealingmaterial 52 may be irradiated with UV after both substrates are bondedtogether. When the sealing material 52 is a resin which requires a timeup to curing after UV irradiation, the sealing material 52 may beirradiated with UV before both substrates are bonded together. In thiscase, there is a merit that damage to the organic layers due to UV lightcan be reduced. As a result, the space between the first substrate 12and the second substrate 50 is filled with the sealing material 52.

When a thermosetting resin is used as the sealing material 52, temporaryfiring may be performed after both substrates are bonded together orboth substrates are partially temporarily fixed using a UV curable resinin a portion.

After the first substrate 12 and the second substrate 50 are bondedtogether, the substrates are fired in a convection oven at 80° C. for 30minutes to finally cure the sealing material 52. As a result, theorganic EL device 10 is manufactured.

The organic EL device 10 manufactured as described above is incorporatedas a display panel of a cellular phone 60, for example, as shown in FIG.11. The organic EL device 10 is also incorporated as a display panel ofa personal information terminal device (PDA), a notebook computer, orthe like or used as a display device of a desktop computer, atelevision, or the like.

In the organic EL device 10 configured as described above, theperipheral region 15 has the peripheral filled region 17 in which thedummy structure 36 is formed so that the volume per unit area of thesealing layer 40 in the peripheral region 15 is substantially the sameas the volume per unit area of the sealing layer 40 in the displayregion 13. Therefore, the sealing material can be charged in both thedisplay region 13 and the peripheral filled region in substantially thesame volume per unit area. Thus, when the second substrate 50 to whichthe sealing material 52 is applied is bonded to the first substrate 12,both the display region 13 and the peripheral filled region 17 of theperipheral region 15 can be filled with the sealing material 52 inproper amounts with as a small space as possible.

As described above, when both the display region 13 and the peripheralregion 15 are filled with the sealing material 52 without a space, it ispossible to reduce moisture and oxygen entering the display region 13through the peripheral filled region 17. Therefore, deterioration of theorganic layers 25 and the like can be reduced, and thus the organic ELdevice 10 having excellent reliability can be manufacture.

Since the dummy structure 36 is configured by one of the elementstructures constituting the organic EL display structure 18 or acombination or two or more of the element structures, the dummystructure 36 can be formed at the same step as the formation of theorganic EL display structure 18. Therefore, the above-describedconfiguration can be easily realized.

In this embodiment, description is made of the case where thesubstantially rectangular frame-shaped peripheral region 15 is formed tosurround the display region 13, and the whole of the peripheral region15 is the peripheral filled region 17. However, a portion of theperipheral region 15 in the circumferential direction or the widthdirection may be the peripheral filled region 17. That is, theperipheral region 15 may have the peripheral filled region 17 in atleast a portion thereof. Therefore, in the other portion of theperipheral region 15, the dummy structure 36 may not be formed at all,i.e., the conditions for the peripheral filled region 17 may not besatisfied.

Of course, when the peripheral filled region 17 is formed tosubstantially surround the display region 13, entering of moisture oroxygen in the display region 13 can be securely reduced by the sealinglayer 40 which fills the peripheral filled region 17.

In addition, the linear dummy structures 36 a are formed in a linearshape having a zigzag shape, and the dot-like dummy structures 36 b areprovided to be scattered at a plurality of positions. Therefore, thebonding area between the sealing layer 40 and the dummy structure 36 onthe first substrate 12 can be increased, thereby enhancing the adhesivestrength of the first substrate 12.

Further, since the linear dummy structures 36 a are formed to in azigzag shape and they substantially surround the display region 13, theadhesive strength of the first substrate 12 through the sealing layer 40can be enhanced. Further, since the linear dummy structures 36 a areformed continuously and uniformly along a direction in which the displayregion 13 is surrounded, entering of moisture or oxygen in the displayregion 13 can be securely reduced.

The lower element structures constituting the dummy structure 36 may beformed to extend over the whole or extend in a plane in the peripheralfilled region 17, and only the upper element structures constituting thedummy structure 36 may be formed in a zigzag shape or a dot shape.

The first insulating layer 22, the second insulating layer 28, and thespacer portion 30 which constitute the organic EL display structure 18are generally formed to be thicker than the other element structures.Therefore, by using the first insulating layer 22, the second insulatinglayer 28, and the spacer portion 30, preferably using only the firstinsulating layer 22, the second insulating layer 28, and the spacerportion 30, the dummy structure 30 can be relatively easily formed, soas to satisfy the above-mentioned condition.

The dummy structure 36 may be formed using the first insulating layer 22and the second insulating layer 28, more preferably using only the firstinsulating layer 22 and the second insulating layer 28. Since the firstinsulating layer 22 and the second insulating layer 28 are relativelythick, the dummy structure 36 can be relatively easily formed to satisfythe condition. That is, the dummy structure 36 is preferably formed toinclude at least one of the materials of the spacer portion 30, thefirst insulating layer 22, and the second insulating layer 28.

Of course, the dummy structure 36 may include the circuit layers 20, thefirst electrode layers 23, or the second electrode layer 26 other thanthe above element structures. The dummy structure 36 preferably does notinclude a portion made of an organic material, such as the organiclayers 25 and the like. Therefore, it can be expected to obtain theeffect of more securely reducing entering and diffusion of moisture oroxygen.

Further, the peripheral filled region 17 includes the first peripheralregion 15 a and the second peripheral region 15 b more apart from thedisplay region 13 than the first peripheral region 15 a in the outwarddirection. In addition, the volume per unit area to be filled with thesealing layer 40 in the second peripheral region 15 b is set to belarger than that in the first peripheral region 15 a. Therefore, thefirst peripheral region 15 a having a smaller volume per unit area to befilled is more securely filled with the sealing material. Further, inthe second peripheral region 15 b, the space between the first substrate12 and the second substrate 50 is more securely filled with the sealingmaterial applied to the second substrate 50, thereby causing littleprotrusion of the sealing material in the side direction. That is, inthe display region 13, it is possible to reduce protrusion (outwardflow) of the sealing material in the side direction while maintainingsecure sealing properties.

Since the peripheral sealing portions 54 in which the sealing layer 40is substantially in contact with the first substrate 12 are formedaround the display region 13, entering of moisture or oxygen can besufficiently reduced by the peripheral sealing portions 54.

1. An organic EL device comprising: a first substrate comprising adisplay region and a peripheral region; an organic EL display structurelocated in the display region of the first substrate; a sealing layerdisposed to seal the organic EL display structure and cover the displayregion and the peripheral region of the first substrate; a secondsubstrate fixed to the first substrate through the sealing layer; and adummy structure located in the peripheral region, wherein the dummystructure has a scattered shape and a linear shape, wherein the volumeper unit area to be filled with the sealing layer in the peripheralregion corresponding to the scattered shape is larger than the volumeper unit area to be filled with the sealing layer in the peripheralregion corresponding to the linear shape.
 2. The organic EL deviceaccording to claim 1, wherein the linear shape surrounds the displayregion and the scattered shape is located closer to an edge of the firstsubstrate than the linear shape.
 3. The organic EL device according toclaim 1, wherein the element structures of the dummy structure containsat least one of the layers of the organic EL display structure.
 4. Theorganic EL device according to claim 1, wherein the dummy structure islocated in the peripheral region so that the volume per unit area of thesealing layer of 1 mm² is substantially the same as the volume per unitarea of the sealing layer of 1 mm² in the display region.
 5. The organicEL device according to claim 1, wherein the ratio of the volume per unitarea of the sealing layer in the peripheral region to the volume perunit area of the sealing layer in the display region is in a range of0.81 to 1.09.
 6. The organic EL device according to claim 1, wherein theorganic EL display structure comprises: a circuit layer located on thefirst substrate; a first insulating layer located on the first substrateto cover the circuit layer; an organic EL element located on the firstinsulating layer; a second insulating layer located on the firstinsulating layer to define an emission region of the organic EL element;and a spacer portion located on the second insulating layer.
 7. Theorganic EL device according to claim 6, wherein a constituent materialof the dummy structure contains at least one of the constituent materialof the first insulating layer, the constituent material of the secondinsulating layer, and the constituent material of the spacer portion. 8.The organic EL device according to claim 1, wherein a peripheral sealingportion is located around the display region, the first substrate beingin direct contact with the sealing layer in the peripheral sealingportion.
 9. The organic EL device according to claim 1, wherein thelinear shape has a plurality of bent portions.
 10. The organic EL deviceaccording to claim 1, wherein the linear shape is formed in a zigzagshape to bend inward and outward to the display region.